JP2003001663A - Resin molding apparatus and resin molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin molding apparatus and a resin molding method capable of homogenously transferring a wide transfer surface even in a case having a flow distribution or a temperature distribution at the time of injection filling by providing a means for adjusting the generation place and degree of a sink generated at the time of molding of a resin. SOLUTION: Slits 4a and 4b are formed to a mold 1 and compressed air flows having pressures different by the respective ventilation routes connected to the slits 4a and 4b are sent into a cavity 2 from the slits 4a and 4b during the inflow of a molten resin into the cavity 2 or during and after the inflow of the molten resin. The degree of the sink generated by the solidification and contraction of the resin is adjusted at every slit connected to each of the ventilation routes by locally releasing the adhesion state of the resin and the mold 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molding apparatus and a resin molding method, and more particularly to a molded product which requires a uniform transfer over a wide area, or a molded product in which certain unit shapes are arranged in an array or a plane. Molded products such as gears in which unit shapes (for example, teeth) are lined up on the circumference, for which unit shapes are required to be uniformly transferred to any part, and for power drive of gears, pulleys, etc. The present invention relates to a resin molding apparatus and a resin molding method which are effective for manufacturing a highly accurate plastic molded product having a cylindrical shape such as a molded product.

[0002]

2. Description of the Related Art Generally, in resin molding,
It is difficult to mold a molded product with a wall-thickness portion with high accuracy, and sink marks and shrinkage distribution are also applied to the parts that require functional accuracy and the part that requires transfer of a fine surface shape (hereinafter referred to as the transfer surface). The phenomenon of poor transfer accuracy is likely to occur.

For example, a plastic gear, which is one of the power-driving parts, is superior in self-lubricating property, low noise, light weight, corrosion resistance, mass productivity, etc. to a metal gear, so that it is a copying machine or a printer. Used in the power transmission part of precision machinery such as. Usually, when these plastic gears are manufactured by injection molding, the outer peripheral surface (tooth surface) and the inner peripheral surface (bearing part)
Since it becomes the transfer surface, molten resin is injected into the mold disk portion from a plurality of pin gates as described below, the entire cavity is filled with the resin, and then the resin is solidified through a solidifying step to obtain a molded product.

FIG. 4 is a view for explaining an example of a conventional normal gear molding, and is a schematic plan view of an essential part of a molded gear and a lower mold of a resin molding apparatus for molding the gear, as viewed from above. Is. Here, the gear pitch circle is shown by a dotted line. In a generally used injection molding method using a plurality of pin gates, the formed gear pitch circle is as shown by the solid line in FIG. That is, the molten resin filled in the disk portion (web portion) spreads radially around the gate 3 and enters the outer peripheral portion (tooth profile forming portion) of the cavity 2. As a result, the gate radial direction part A and the radial direction part between the gates
(Welding part) At B, a resin flow distribution to the outer peripheral part occurs,
As a result, since the resin temperature and shrinkage ratio are different between parts A and B, the gear pitch circle on the outer periphery of the molded product does not have the circular shape shown by the dotted line, but the gate position shown by the solid line. Corresponding petal-shaped irregularities are formed. As it is, it is not possible to manufacture a highly accurate molded product in which the outer peripheral surface is uniformly transferred.

Further, since the portion where the rim portion and the disc portion intersect is usually the thickest, this is the portion where the cooling of the resin by the mold is the slowest, and the resin portion is the last to cool and harden. Due to the contraction at this time, the surrounding resin is drawn into the central portion of the wall thickness, so that the surface shape of the pulled portion becomes a concave depression (called a sink mark). In the case of a normal gear shape, sink marks are easily generated on the outer peripheral tooth surface, which requires precision, which is a problem.

Therefore, in the gas pressure injection molding method described in Japanese Patent Laid-Open No. 10-156861, the back side of the resin portion requiring transfer accuracy or the vicinity of the back side is moved to the transfer surface side by the pressure of fluid or gas. We propose a pressing method.

However, the above-mentioned Japanese Laid-Open Patent Publication No. 10-1568.
In the molding method disclosed in Japanese Patent No. 61, a back surface (non-transfer surface) corresponding to a resin portion (transfer surface side) requiring transfer accuracy or a vicinity of the back surface is transferred by a fluid or gas pressure. Since it is a method of pressing to the side, expensive equipment such as a high-pressure fluid source and a control device that controls the pressure and introduction timing of the fluid from the fluid source is required, and when using high-pressure gas as the fluid, However, there is a problem in that usability is poor because there are many restrictions before the installation of equipment because permission for using high-pressure gas and permission for the installation location of the device are required.

On the other hand, when the applicant first flows molten resin into the cavity of the mold and solidifies and molds it,
An outside air introduction part (for example, a slit) is formed in the mold by opening it in any part other than the transfer surface of the cavity and communicating the outside of the mold with the inside of the cavity. By forming a step in the direction perpendicular to the flow direction of the molten resin and selectively generating sink marks in the resin of the outside air introduction part, low pressure molding without using a special and expensive device Under conditions, it is possible to prevent sink marks from being generated on the surface to be transferred (transfer surface), and to manufacture a molded product having a highly accurate transfer surface at low cost with low energy consumption and with good durability. A resin molding device and a molding method are proposed.

In the method previously proposed by the applicant of the present invention, an outside air introduction portion (a back side of the outer peripheral tooth surface is effective for the tooth surface) is provided circumferentially at an arbitrary position of the disk portion. As a result, the transferability of the tooth surface is enhanced by inducing sink marks on the disk portion other than the outer peripheral surface (transfer surface).

As described above, in the method previously proposed by the applicant of the present invention, the web portion is provided with an opening such as an outside air introducing portion to release the adhesiveness between the mold and the resin.
When the resin in that part is pulled to the center of the wall thickness more than other parts such as the tooth surface, it is easy to separate from the mold surface and sink. Furthermore, by sending in compressed gas from the outside, the situation of being more prone to sinking will be accelerated. Usually, cooling of the inside of the mold lowers the residual resin pressure, and sink marks begin to occur when the pressure on the resin surface becomes zero.However, by sending compressed gas from the outside, the timing is It will be faster, and the resin will move away from the mold surface while the resin temperature is higher and the elastic modulus is lower. Therefore, the resin is easy to move and the sink mark is relatively large. As the degree of sink mark increases, the transferability of the outer peripheral surface to be transferred improves depending on the degree (the contraction rate also changes partially).

However, since there is a flow distribution due to a plurality of gates in the circumferential direction of the disk shape, and a temperature distribution and a pressure distribution are produced in the circumferential direction, the occurrence of sink marks such as introduction of compressed gas under the same conditions in the circumferential direction is given. In this case, there is a distribution in the degree of sink mark generation and a distribution in the degree of transferability improvement to the outer peripheral surface (the degree of shrinkage change). As a result, the roundness on the outer peripheral surface is There is a limit to the reduction of, and it becomes difficult to adjust the conditions.

For example, if the method previously proposed by the applicant of the present invention is applied to the molding of the gear shown in FIG. 4, the effect of improving the tooth surface transferability is certainly obtained by sinking the portion other than the tooth surface. However, the degree of sink mark is different due to the influence of the flow distribution or the temperature distribution, and the gate radial direction portion A and the radial direction portion (weld portion) B between the gates have different sink depths. There is a limit in reducing the difference in transferability of the tooth surface in the B portion.

[0013]

As described above, although the conventional method as described above has the effect of improving the transferability of the transfer surface, it does not transfer in the molding having a flow distribution or temperature distribution during injection filling. However, there is a drawback in that the distribution of sink marks tends to occur. When the distribution of the sink marks is generated, the degree of improvement in transferability on the transfer surface is also affected, and in the case of a molded product that requires uniform transfer on the entire transfer surface, there is a problem in homogeneity.

The present invention has been made in view of the above-mentioned circumstances, and has means for adjusting the degree of sink mark at each resin portion individually or in groups at the time of resin molding, so that the injection filling can be performed. It is an object of the present invention to provide a resin molding apparatus and a resin molding method capable of uniformly transferring a transfer surface in a wide area even when it has a flow distribution or a temperature distribution.

[0015]

According to a first aspect of the present invention, an outside air introducing portion is formed in an arbitrary portion of the cavity to communicate with the outside of the mold and the inside of the cavity, and the molten resin flows into the cavity. In the resin molding apparatus for solidifying by the above, two or more of the outside air introducing portions are formed, each has an independent ventilation passage, and the ventilation passage can be opened and closed individually.

According to a second aspect of the present invention, an outside air introducing portion is formed which opens in an arbitrary portion of the cavity and connects the outside of the mold with the inside of the cavity, and the molten resin flowing into the cavity is introduced into the cavity. In a resin molding apparatus that has a step portion in a direction orthogonal to the flow direction of, and in which molten resin flows into the cavity to be solidified, two or more outside air introducing portions are formed, each of which has an independent ventilation path. The ventilation path can be opened and closed individually.

According to a third aspect of the present invention, in the first or second aspect of the invention, the two or more outside air introducing portions are like a portion into which the resin flows first and a portion into which the resin flows later (around the weld portion). It is characterized in that it is formed at a position corresponding to the flow distribution of the resin.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, the two or more outside air introducing portions are like a portion into which the resin flows first and a portion into which the resin flows later (around the weld portion). The two or more outside air introducing portions are formed at positions corresponding to the flow distribution of the resin and have independent ventilation paths for each group, and the ventilation paths can be opened and closed for each group. is there.

According to a fifth aspect of the invention, in the first or second aspect of the invention, the two or more outside air introducing portions are formed at positions corresponding to the temperature distribution after the molten resin is filled. It was done.

According to a sixth aspect of the invention, in the first or second aspect of the invention, the two or more outside air introducing portions are formed at positions corresponding to the temperature distribution after the molten resin is filled, and the two or more outside air introducing portions are formed. The outside air introducing section has an independent ventilation path for each group, and the ventilation path can be opened and closed for each group.

According to a seventh aspect of the invention, in the first to sixth aspects of the invention, after the molten resin flows into the cavity, or during and after the inflow, the outside air introducing portion is provided for each independent ventilation path. A gas feeding means for forcibly feeding gas into the cavity is provided.

According to an eighth aspect of the present invention, in the seventh aspect of the present invention, the gas feeding means passes through the outside air introducing portion to the inside of the cavity after the molten resin flows into the cavity, or during and after the flowing. When the gas is fed into the device, it has a means for individually adjusting the pressure of the gas fed to each ventilation path.

According to a ninth aspect of the present invention, in the invention of the eighth aspect, a plurality of resin temperature measuring means are provided in the vicinity of the outside air introducing portion, and the independent outside air introducing portion is provided inside the cavity for each of the ventilation paths. It is characterized in that it has a control means for controlling so that the gas having a pressure corresponding to the resin temperature measured by the resin temperature measuring means is fed.

The invention of claim 10 is characterized in that a resin is molded by using the resin molding apparatus of any one of claims 1 to 9.

According to an eleventh aspect of the present invention, the transfer surface is made more uniform by using the resin molding apparatus according to the first to ninth aspects.
It is characterized in that the resin is molded by adjusting the opening / closing timing of each of the ventilation paths and the pressure of the introduced gas.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the examples of FIGS. 1 to 3 showing the main part of a resin molding apparatus.

(Embodiment 1) FIG. 1 is a plan view of a lower die of a resin molding apparatus according to Embodiment 1 of the present invention as seen from above.
It is a figure corresponding to Claims 1 and 2, and Claim 10. A cavity 2 corresponding to a gear is formed by the lower die 1 of the resin forming device and an upper die (not shown), and the lower die 1 is formed.
A plurality of gates 3 that are the inlets of the molten resin are formed at positions corresponding to the disk portion of the gear. Mold 1 has
The slit 4a corresponding to the gate radial direction portion A has a slit penetrating the outside of the mold 1 and the inside of the cavity 2, and
The slits 4b corresponding to the radial direction portion (weld portion) B between the gates are formed on the same circumference. The slits 4a and 4b each have an independent ventilation path (shown in FIG. 3), and the ventilation path can be opened and closed by being individually controlled by the control device.

The clearances of the slits 4a and 4b are formed to be 0.001 to 0.03 mm, preferably 0.001 to 0.02 mm at the cavity opening. As a result, it is possible to prevent the resin from entering and forming burrs during injection / filling.

The molten resin injected from the gates 3 into the cavities 2 spreads radially from each gate 3, shunts near the non-transfer surface, changes the flow in the circumferential direction, and finally flows between adjacent gates. Reaches the weld part, which is the middle part of
It is solidified and cooled. At this time, while the molten resin is flowing into the cavity 2, or during and after the flowing, the slit 4
By sending compressed gas into the cavity 2 from a and 4b and locally releasing the close contact state between the resin and the mold 1, when the resin is solidified in the mold 1, the resin shrinks. The sink mark is generated by the portion where the close contact state is released, and the degree of occurrence of the sink mark is adjusted by feeding a compressed gas having a different pressure for each ventilation path.
It is possible to adjust every a and 4b.

As described above, since the outside air introducing portions such as two or more slits have independent ventilation paths and the ventilation paths can be opened and closed individually, the degree of sink mark on each non-transfer surface can be controlled. It can be adjusted individually. Here, if a step is formed in the cavity 2 in a direction orthogonal to the flow direction of the molten resin, sink marks can be more reliably generated on the non-transfer surface. As a result, even in molding that has a flow distribution or temperature distribution during injection filling,
It is possible to transfer the transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

(Embodiment 2) FIG. 2 is a plan view of a lower mold of a resin molding apparatus according to a second embodiment of the present invention as seen from above.
It is a figure corresponding to Claims 3-6. In the figure, the components having the same functions as those in FIG. 1 are given the same numbers as the numbers given in FIG. In the present embodiment, the outside air introducing portion has slits 4a at positions on the same circumference for each portion A where the resin flows in first and portion B where the resin flows later (such as around the weld portion). , 4b. The slits 4a and 4b are divided into groups such as the A section and the B section, and the ventilation paths 5a and 5b are independent for each group.
The ventilation paths 5a and 5b can be opened and closed under the control of the control device for each group (this point will be described later with reference to FIG. 3).

The molten resin injected from the gate 3 into the cavity 2 spreads radially from each gate 3, splits near the non-transfer surface, changes its flow in the circumferential direction, and finally flows between adjacent gates. Reaches the weld part, which is the middle part of
It is solidified and cooled. At this time, while the molten resin is flowing into the cavity 2, or during and after the flowing, the slit 4
By sending compressed gas into the cavity 2 from a and 4b and locally releasing the close contact state between the resin and the mold 1, when the resin is solidified in the mold 1, the resin shrinks. The sink mark is generated by the part where the close contact state is released, but the degree of this sink mark can be adjusted for each group by sending compressed gas of different pressure to each ventilation path for each group. Is.

As described above, in the second embodiment, the outside air introducing portion is divided into a position where the resin inside the cavity is likely to sink (a portion where the resin flows first) and a position where it is difficult to sink (a portion where the resin flows afterwards). It is arranged as
The degree of sink mark generation on each non-transfer surface can be efficiently and individually adjusted. Therefore, the number of outside air introducing portions can be reduced, and the die manufacturing period and cost can be reduced. In addition, by connecting a plurality of outside air introduction portions at the same level of sinkiness to one ventilation path as a group, the ventilation path can be reduced, and the die manufacturing period and cost can be reduced. Also, it is possible to reduce ancillary equipment. As a result, even in the case of molding having a flow distribution or temperature distribution during injection filling, it is possible to transfer a transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

(Embodiment 3) FIG. 3 is a gas feeding means for controlling the gas fed into the ventilation path connected to the slits 4a, 4b of the resin forming apparatus shown in FIG. 1 according to the third embodiment of the present invention. FIG. 9 is a diagram for explaining the above, and corresponds to claims 7 to 9 and claim 11. In this example,
As shown in FIG. 1, the outside air introduction portion corresponds to the flow distribution of the resin, such as the portion A where the resin flows in first and the portion B where the resin flows later (such as around the weld part). The slits 4a and 4b are formed at the respective positions. Further, the slits 4a and 4b are provided in the A section and the B section.
Connected to independent ventilation paths 5a and 5b for each group such as parts, and the ventilation paths 5a and 5b are provided with opening / closing means 6a and 6b.
Further, the gas pressure adjusting means 7a, 7b and the opening / closing means 6a, 6b connected to the compressed gas source 8 are
It is controlled by the controller 9.

The molten resin injected from the gate 3 into the cavity 2 spreads radially from each gate 3, splits near the non-transfer surface, changes its flow in the circumferential direction, and finally flows between adjacent gates. Reaches the weld part, which is the middle part of
It is solidified and cooled. At this time, while the molten resin is flowing into the cavity 2, or during and after the flowing, the gas pressure adjusting means 7a, 7b connected to the controller 9 sets the compressed gas of the compressed gas source 8 to an appropriate pressure, and the controller 9
The opening / closing means 6a, 6b are controlled by the slits 4a, 4
By opening / closing the ventilation paths 5a, 5b of b, the compressed gas is sent into the cavity 2 from the slits 4a, 4b, and the close contact state between the resin and the mold 1 is locally released. When the resin is solidified in the mold 1, shrinkage due to solidification shrinkage of the resin is caused by the portion where the close contact state is released. The degree of occurrence of the sink mark can be adjusted for each group by feeding compressed gas having a different pressure for each ventilation path for each group.

As described above, after the molten resin flows into the cavity through the outside air introducing portion for each independent ventilation path,
Alternatively, opening / closing means 6a and 6b for forcibly feeding gas into the cavity during and after inflow can be provided to more reliably adjust the degree of sinking of each part, and have a flow distribution and temperature distribution during injection filling. Also in molding, it is possible to uniformly transfer a transfer surface in a wide area, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

Further, in order to make the transfer surface more uniform, the controller 9 controls the opening / closing timing of each ventilation path 5a, 5b and the pressure of the gas to be introduced so as to manufacture a resin molded product from the molten resin. As a result, the degree of sink mark generation on each non-transfer surface can be adjusted more finely and appropriately. As a result, even in the case of molding having a flow distribution and a temperature distribution during injection filling, it is possible to transfer the transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

Further, a resin temperature measuring means for measuring the resin temperature is provided at an arbitrary plurality of positions on the wall surface of the mold 1 near the slits 4a and 4b, and a controller 9 is provided so as to introduce a gas having a pressure corresponding to the resin temperature. By controlling with, the degree of sink mark on the non-transfer surface can be automatically and appropriately controlled when a disturbance of equipment or the external environment or an unstable factor such as the start of molding occurs. Therefore, even in molding having a flow distribution and a temperature distribution during injection filling, it is possible to stably and uniformly transfer a transfer surface in a wide area, and it is possible to stably obtain a molded product that is homogeneous and has high transfer accuracy.

In the present invention, the non-transfer surface is classified into a place where sink marks are likely to occur and a place where sink marks are not generated according to the flow distribution or the resin temperature distribution, and the pressure of the compressed gas and the like are set to appropriate conditions for each place. And adjust the degree of sink marks. As a result, it is possible to reduce the petal-like uneven shape on the outer peripheral surface to the minimum, and it is possible to obtain a molded product with high roundness.

In the gear described as an example of the resin molded product manufactured by using the resin molding apparatus according to the present invention, it is possible to obtain a gear with less runout and good homogeneity of all tooth surfaces. Further, the resin molding apparatus according to the present invention is also effective when manufacturing circular or cylindrical parts having homogeneity other than gears. Further, the resin molding apparatus according to the present invention is a molded product that requires a uniform transfer over a wide area, or
This is particularly effective in the case of manufacturing a molded product in which a certain unit shape is arranged in an array or a plane, and a molded product in which the unit shape is required to be uniformly transferred in any part.

[0041]

According to the invention of claim 1, according to the invention of claim 1, an outside air introducing portion is formed in an arbitrary portion of the cavity to communicate with the outside of the mold and the inside of the cavity, and the molten resin is provided in the cavity. In the resin molding apparatus for inflowing and solidifying air, two or more outside air introducing portions are formed, each has an independent ventilation path, and the ventilation paths can be opened and closed individually, so that the occurrence of sink marks on each non-transfer surface. The degree can be adjusted individually. As a result, even in the case of molding having a flow distribution and a temperature distribution during injection filling, it is possible to transfer the transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

The effect of the invention of claim 2 According to the invention of claim 2, an outside air introducing portion is formed in an arbitrary portion of the cavity so as to communicate the outside of the mold with the inside of the cavity, and the inside of the cavity is formed inside the cavity. In a resin molding apparatus that has a step portion in a direction orthogonal to the flowing direction of the molten resin flowing into the cavity and in which the molten resin flows into the cavity to be solidified, two or more outside air introducing portions are formed, each of which is independent. Since the ventilation path can be opened and closed individually and the wall thickness varies depending on the stepped portion, sink marks can be generated more reliably on the non-transfer surface. The degree of sinkage can be adjusted individually. As a result, even in the case of molding having a flow distribution and a temperature distribution during injection filling, it is possible to transfer the transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

Effect of the Invention of Claim 3 According to the invention of claim 3, two or more outside air introducing portions are separately arranged at a position where the resin in the cavity is likely to sink and a position where it is difficult to sink the resin in the cavity. It is possible to efficiently and individually adjust the degree of occurrence of sink marks on the surface. Therefore, the number of outside air introducing portions can be reduced, and the die manufacturing period and cost can be reduced. Further, even in the case of molding having a flow distribution and a temperature distribution at the time of injection filling, it is possible to transfer a transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

Effect of the Invention of Claim 4 According to the invention of claim 4, two or more outside air introducing portions are separately arranged at a position where the resin in the cavity is likely to sink and a position where it is difficult to sink the resin in the cavity. It is possible to efficiently and individually adjust the degree of occurrence of sink marks on the surface. Therefore, the number of outside air introducing portions can be reduced, and the die manufacturing period and cost can be reduced. In addition, by connecting a plurality of outside air introducing portions at the same level of ease of sinking to one ventilation passage as a group, the ventilation passage can be reduced, and the die manufacturing period and cost can be reduced. ,
In addition, auxiliary equipment can be reduced. Further, even in the case of molding having a flow distribution and a temperature distribution at the time of injection filling, it is possible to transfer a transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

Effect of the Invention of Claim 5 According to the invention of claim 5, since two or more outside air introducing portions are separately arranged at a position where the resin in the cavity is likely to sink and a position where it is difficult to sink, the non-transfer It is possible to efficiently and individually adjust the degree of occurrence of sink marks on the surface. Therefore, the number of outside air introducing portions can be reduced, and the die manufacturing period and cost can be reduced. Further, even in the case of molding having a flow distribution and a temperature distribution at the time of injection filling, it is possible to transfer a transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

Effect of the Invention of Claim 6 According to the invention of claim 6, since two or more outside air introducing portions are separately arranged at a position where the resin in the cavity is likely to sink and a position where it is difficult to sink, the non-transfer It is possible to efficiently and individually adjust the degree of occurrence of sink marks on the surface. Therefore, the number of outside air introducing portions can be reduced, and the die manufacturing period and cost can be reduced. In addition, by connecting a plurality of outside air introducing portions at the same level of ease of sinking to one ventilation passage as a group, the ventilation passage can be reduced, and the die manufacturing period and cost can be reduced. ,
In addition, auxiliary equipment can be reduced. Further, even in the case of molding having a flow distribution and a temperature distribution at the time of injection filling, it is possible to transfer a transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

The effect of the invention of claim 7 According to the invention of claim 7, it is possible to more reliably adjust the degree of sink mark of each part, and even in the case of molding having a flow distribution and a temperature distribution at the time of injection filling, a wide area transfer is performed. It is possible to transfer the surface uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

The effect of the invention of claim 8 According to the invention of claim 8, it is possible to more reliably adjust the degree of sink mark at each part, and even in the case of molding having a flow distribution and a temperature distribution at the time of injection filling, a wide range transfer is achieved. It is possible to transfer the surface uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

Effect of the Invention of Claim 9 According to the invention of claim 9, the degree of sink mark on the non-transfer surface is automatically determined even when disturbance of equipment or external environment or an unstable factor such as the start of molding occurs. Can be properly controlled.
Therefore, even in molding having a flow distribution and a temperature distribution during injection filling, it is possible to stably and uniformly transfer a transfer surface in a wide area, and it is possible to stably obtain a molded product that is homogeneous and has high transfer accuracy.

Effect of the Invention of Claim 10 According to the invention of claim 10, the degree of occurrence of sink marks on each non-transfer surface can be adjusted individually. As a result, even in the case of molding having a flow distribution and a temperature distribution during injection filling, it is possible to transfer the transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

The effect of the invention of claim 11 According to the invention of claim 11, the resin is molded by adjusting the opening / closing timing of each ventilation path and the pressure of the introduced gas so that the transfer surface becomes more uniform. The degree of sink mark generation on each non-transfer surface can be adjusted more finely and appropriately. As a result, even in the case of molding having a flow distribution and a temperature distribution during injection filling, it is possible to transfer the transfer surface in a wide area uniformly, and it is possible to obtain a molded product that is uniform and has high transfer accuracy.

[Brief description of drawings]

FIG. 1 is a plan view of a lower mold of a resin molding apparatus according to a first embodiment of the present invention as viewed from above.

FIG. 2 is a plan view of a lower mold of a resin molding apparatus according to a second embodiment of the present invention as viewed from above.

FIG. 3 is a diagram for explaining gas feeding means for controlling gas fed into a ventilation path connected to a slit of a resin forming apparatus according to a third embodiment of the present invention.

FIG. 4 is a schematic plan view of an essential part of a molded gear and a lower mold of a resin molding device that molds the gear, as viewed from above.

[Explanation of symbols]

1 ... Mold, 2 ... Cavity, 3 ... Gate, 4a, 4b ...
Slits 5a, 5b ... Ventilation path, 6a, 6b ... Opening / closing means, 7a, 7b ... Gas output means, 8 ... Compressed gas source, 9 ...
controller.

Claims (11)

[Claims] 1. A resin molding apparatus for forming an outside air introducing portion, which opens in an arbitrary portion of a cavity and communicates the outside of a mold with the inside of the cavity, and injects a molten resin into the cavity to solidify the resin. A resin molding device, wherein two or more introduction parts are formed, each has an independent ventilation path, and the ventilation path can be opened and closed individually. 2. An outside air introducing portion that opens in an arbitrary portion of the cavity and communicates the outside of the mold with the inside of the cavity is formed, and the inside of the cavity with respect to the flow direction of the molten resin flowing into the cavity. In a resin molding apparatus having a step portion in a direction orthogonal to each other and injecting a molten resin into the cavity for solidification, two or more of the outside air introducing portions are formed and each has an independent ventilation path. A resin molding device characterized in that the paths can be opened and closed individually. 3. The resin molding apparatus according to claim 1, wherein the two or more outside air introducing portions correspond to a flow distribution of the resin such as a portion into which the resin flows first and a portion into which the resin flows later. A resin molding device, which is formed at a predetermined position. 4. The resin molding apparatus according to claim 1, wherein the two or more outside air introducing portions correspond to a flow distribution of the resin such as a portion into which the resin flows first and a portion into which the resin flows later. The resin molding apparatus is characterized in that the two or more outside air introducing portions are formed at different positions and have independent ventilation paths for each group, and the ventilation paths can be opened and closed for each group. 5. The resin molding apparatus according to claim 1 or 2, wherein the two or more outside air introducing portions are formed at positions corresponding to a temperature distribution after the molten resin is filled. Resin molding equipment. 6. The resin molding apparatus according to claim 1 or 2, wherein the two or more outside air introducing portions are formed at positions corresponding to a temperature distribution after the molten resin is filled, and the two or more outside air introducing portions are formed. The resin molding apparatus is characterized in that the introduction part has an independent ventilation path for each group, and the ventilation path can be opened and closed for each group. 7. The resin molding apparatus according to claim 1, wherein the outside air is introduced into each of the independent ventilation paths after the molten resin has flown into the cavity, or during and after the inflow of the molten resin. A resin molding device comprising a gas feeding means for forcibly feeding gas into the cavity through a portion. 8. The resin molding apparatus according to claim 7, wherein the gas feeding means is introduced into the cavity through the outside air introduction portion after the molten resin has flown into the cavity or during the inflow and the inflow of the molten resin. A resin molding apparatus comprising means for individually adjusting the pressure of the gas sent to each ventilation path when the gas is sent in. 9. The resin molding apparatus according to claim 8, wherein a plurality of resin temperature measuring means are provided in the vicinity of the outside air introducing section, and the resin is introduced into the cavity through the outside air introducing section for each independent ventilation path. A resin molding apparatus comprising: a control unit that controls so that the gas having a pressure according to the resin temperature measured by the temperature measurement unit is fed. 10. A resin molding method, which comprises molding a resin by using the resin molding apparatus according to claim 1. 11. The resin molding apparatus according to claim 1, wherein the transfer surface becomes more uniform.
A resin molding method comprising molding a resin by adjusting the opening / closing timing of each of the ventilation paths and the pressure of the introduced gas.